Abrasive dust particles such as fly ash, catalysts, particles for fluid bed applications, etc., are difficult to control when such particles are at elevated pressures such as 105 psi and at elevated temperatures from 400.degree. F. to 1600.degree. F. Expansion and contraction of the metal materials while at the same time providing a metal to metal seating action without shock create difficult problems. The abrasive particles tend to interfere with attainment of a bubble tight seal between the head and the seat.
The valve of the present invention is a solution to the above and other problems associated with high temperature, high pressure valves.